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Northeast Tornado Stats: 2013

Here's a recap of the 2013 tornado season across the Northeast. Connecticut had four reports of tornadoes during 2013, which is roughly twice the average amount of about two. Keep in mind that 2012 had no tornadoes in the state, so one could argue that this was nature's way of balancing itself out. Elsewhere, New Jersey was the only other state in the Northeast with above average tornado reports. (They average two per year, but had three in 2013) Maine is not pictured here, but Maine had at least two tornado reports. Since they average two per year, that's right at average. Massachusetts also saw an average year with one tornado report. Vermont and New Hampshire typically average about one tornado per year, but both states saw no tornadoes this year. New York was well below average with just four tornadoes. The average there is 10 per year. Pennsylvania reported nine tornadoes, also well below their average of 16 per year. Averages based off of 1991-2010 reports, per NCDC. April 19th: An EF-1 tornado touched down near Bainbridge, N.Y. and was on the ground for 3.2 miles. (link) May 9th: A weak EF-0 tornado touched down near Stoughton, Mass., but the length of damage was less than 0.5 miles. This was a cold air funnel case and not a "classic" tornado. (link) May 28th: There were four tornado reports across northwestern Pennsylvania. Three of the tornadoes were rated EF-1s and one was an EF-0. The longest tracking tornado was an EF-1 that touched down near Edinboro and had a damage path of 18 miles long. May 29th: Two tornadoes were reported in eastern New York State. One was a significant, long-track tornado (EF-2). It was on the ground for 17 miles and the damage path was up to 1 mile wide. Another tornado, a weaker EF-1, was reported just to the southwest of that storm. (link) June 2nd: Two brief and weak EF-0 tornadoes were reported in Maine. June 27th: Two EF-1 tornadoes were reported in central Pennsylvania. July 1st: A somewhat unusual morning tornado (EF-1) was reported in extreme northeastern New Jersey. The same storm that was responsible for that tornado resulted in three tornado reports across Connecticut from late morning into early afternoon. The first report was an EF-0 that touched down in Greenwich. The most notable tornado was the second one, which was an EF-1 in the Windsor and Windsor Locks areas. A weak, brief EF-0 tornado was the third report in Enfield. (link) July 10th: A brief EF-1 tornado was reported near Moravia, Penn. during the afternoon. Less than an hour later, an intermittent EF-1 tornado was reported in Connecticut between Andover and Mansfield. The damage path of that tornado was 11.2 miles long. July 27th: An EF-1 tornado was reported in north-central Pennsylvania near Borie. That same storm dropped another EF-1 tornado in adjacent New York State about an hour later. The second of those two tornadoes was on the ground for 14 miles. August 7th: A minor EF-0 tornado was reported in southwestern Pennsylvania near Ralphton. August 13th: A weak EF-0 tornado was reported near Manahawkin, N.J. October 7th: An EF-1 tornado was reported near Paramus, N.J. The tornadoes pictured above across Delaware, Maryland and Ohio were not included in the above time-line. As might be expected, the strongest and longest-tracking tornadoes across the Northeast this year were across New York and northwestern Pennsylvania. Those areas are climatologically favored for significant tornadoes, at least when compared to areas further east. With that said, there have certainly been cases of strong tornadoes in southern New England. The most recent case was the deadly EF-3 tornado that tracked across south-central Massachusetts on June 1st of 2011. The above image is a composite that is not perfectly to scale. United States tornado seasons: Through then winter, the Gulf States are favored for tornado development. There was a minor event this past Sunday, on January 12th, that featured a few EF-0 tornado reports in extreme southeastern Virginia. Into spring, the focus shifts toward the Midwest and late spring into early summer is when the Northeast most commonly sees tornadoes.

Quincy

Quincy

 

Connecticut Snowfall Totals: Jan. 2-3, 2014

Here are some snowfall maps that I created using reports from various sources. Many of the reports came from this forum and the National Weather Service. Only social media reports that passed through quality control were considered. Blowing and drifting snow made it difficult to obtain an accurate measurement. Some towns had multiple reports and totals that appeared to be too high based off of surrounding reports were not used. Some warm-advection snow lifted into Connecticut as early as the night of January 1st, the vast majority of the accumulating snow began on January 2nd. From morning through afternoon, flurries and periods of light snow moved from south to north across the state. By afternoon, some areas, mainly across the northern half of the state, reported an inch or two of snowfall. The 12z sounding from January 2nd at OKX indicated somewhat of a dry layer aloft, while ALY was more saturated. The best snows early on were measured from central New York into portions of interior Massachusetts. During the evening, low pressure eventually developed off of the mid-Atlantic coast and an area of snow filled in across Connecticut. It was from about 9 p.m. to 4 a.m. that the heaviest snow fell. The bands of heaviest snow wound up remaining south of Connecticut and there were even more impressive snowfall totals across eastern Massachusetts. There, ocean-enhancement was a key role in significantly higher snowfall amounts. In Connecticut, accumulating snow ended by mid-morning on January 3rd, with most areas receiving anywhere from 4 to 7 inches of snow. There was a narrow band of 7 to 7.5 inches across the northern part of the state, where additional snow during the beginning of the event increased overall totals. Close to the coast, there were also a few totals of 7 to 7.5 inches, where some towns were grazed by heavier snow toward the end of the event. While there were a few snowfall totals reported in the range of 8 to 9+ inches, those did not line up with other totals in the same or neighboring towns. Strong winds caused blowing and drifting snow, which was the most likely cause for the totals that were assumed to be erroneously high. One variable that was generally missed by the computer forecast models was lower liquid-to-snow ratios. While these ratios are generally close to 10:1, model forecasts predicted anywhere from 15-20:1 ratios, or even higher. If higher ratios had been observed, snowfall totals across Connecticut would have been higher. In the end, ratios were fairly close to 10:1. It was quite cold during the storm with temperatures falling into the lower 10s and single digits by the morning of January 3rd. Although there is a loose correlation between surface temperatures and snow ratios (colder yielding higher ratios), it was the snow growth above the surface that did not promote higher ratios. Surface temperatures alone have no impact on snow ratios, unless the temperatures are near or above freezing, then they can actually lower the ratios. If any amounts you reported conflict with these amounts, please comment back with your total(s). Here is an alternate black and white version of the map:

Quincy

Quincy

 

Connecticut Snowfall Totals: Dec. 17, 2013

Here are some snowfall maps that I created using reports from various sources. Many of the reports came from this forum and the National Weather Service. Only social media reports that passed through quality control were considered. A clipper system that gave way to a coastal low just south of Long Island resulted in generally 2 to 4 inches of snow across the state. There were a few localized totals of just over 4 inches, but there were no reports over 5.0 inches. The highest totals were across the higher terrain, where some modest orographic enhancement and/or higher snowfall ratios may have come into play. There was a "snow hole" in southeastern Connecticut where generally 2 inches or less was measured. A few of the higher resolution models hinted at this area of localized lower amounts, but most data pinned that area further north. Snow flurries developed around daybreak on December 17th and periods of light snow continued through midday. After a break in the action, an area of moderate to locally heavy snow formed by mid-afternoon as low pressure intensified just to the south. Snowfall rates approached one inch per hour for a time. Some warmer air worked north and there was a change to sleet and freezing rain cross portions of lower Fairfield County. Snow tapered to flurries during the evening hours. If any amounts you reported conflict with these amounts, please comment back with your total(s). Here is an alternate black and white version of the map:

Quincy

Quincy

 

Connecticut Snowfall Totals: Dec. 14-15, 2013

Here are some snowfall maps that I created using reports from various sources. Many of the reports came from this forum and the National Weather Service. Only social media reports that passed through quality control were considered. It should be noted that some of the reports include sleet. A general 4 to 8 inch snowfall blanketed the state before a changeover to sleet and in some cases freezing rain/rain. Very few totals deviated from that range, except for a few 8"+ reports in northwestern Connecticut and totals less than 4" across coastal New London County. Precipitation came in multiple waves between December 14th and 15th. Periods of light snow fell from morning through early afternoon. Radar imagery showed pronounced dryslots and breaks in the snow shield through much of the afternoon and early evening hours before a slug of heavier precipitation moved back in. This lack of steady snow likely cut down on some of the snowfall totals. Warmer air began to work north overnight as low pressure developed along the New Jersey coast. It took quite some time to erode the cold air that was in place prior to the event. Even though areas such as KGON and KIJD changed to rain, KHVN never rose above freezing during the steady precipitation. There, there was even a pronounced temperature drop of 7 degrees within an hour around midnight as the wind shifted to the north, allowing for colder air to drain into the city. As a result, New Haven and nearby North Haven reported an ice accretion of 0.3 inches. Other areas between I-95 and I-84 saw some icing, but most of the freezing rain was confined to lower Fairfield and lower New Haven Counties. If any amounts you reported conflict with these amounts, please comment back with your total(s). Here is an alternate black and white version of the map:

Quincy

Quincy

 

Significant Storm for Tuesday into Wednesday

For far western areas along I-81 between I-64 and OKV An area of low pressure will move out of the northern Gulf of Mexico and up the east coast tomorrow and Wednesday. As it does, light precipitation will begin to overspread the area early tomorrow morning and will increase in intensity throughout the day … before beginning to taper during the overnight and possibly end as a period of snow Wednesday. Initially, there will be just enough cold air in place for some spotty flurries during the predawn hours Tuesday morning. Precipitation type will quickly shift towards freezing rain and sleet by 7:30am. As warmer air continues to move in with heavier precipitation through the day, freezing rain will transition to a plain cold rain. As typical, deeper and sheltered valleys will hold to freezing rain the longest … possibly into the late morning hours. Steady rain will decrease in intensity after midnight Tuesday night as colder air begins to filter in on the back side of the storm. Any leftover precipitation will begin to mix with sleet and snow again early Wednesday morning and eventually end as light snow/snow showers, as precipitation fully shuts off Wednesday afternoon. Wintry accumulations Tuesday will likely not amount to much at all … up to a coating of snow/sleet and up to 0.1” of ice accretion in the very coldest valleys (where freezing rain will hold on the longest). I do not expect roads to be that much of a problem tomorrow … icy spots should be limited to bridges and overpasses I think. This is not a great setup for a high impact freezing rain event … but that does not mean that slick spots cannot develop. Snow/sleet accumulations that occur Wednesday will likely total an inch or less for most. This part of the storm remains the most uncertain in terms of sensible weather. If colder air filters in more quickly than expected, then we will see a change over to snow earlier. There is also a question as to how much moisture will still be available and how efficient snowflake production will be aloft … both factors will have a big impact on the end result.

thunderman

thunderman

 

QBO in a two dimensional framework

The Quasi-Biennial Oscillation (QBO) is a cycle of zonal wind in the equatorial stratosphere with a period that varies between 24 and 30 months. This oscillation is a product of downward propagating alternating wind regimes. The current method of monitoring this oscillation is through an index, calculated by the zonal wind anomaly at 30hPa averaged along the equator. This method excludes information on the vertical structure of winds in the stratosphere, and presents the QBO as a one-dimensional temporal oscillation. Presented here is a new framework for monitoring the QBO. This framework incorporates both the oscillation in time and in space. The two leading principle components (PCs) of equatorial stratospheric zonal winds are calculated from NCEP/NCAR reanalysis monthly mean data. These PCs are then standardized and used as X and Y coordinates in a 2-dimensional phase space. A phase angle can then be calculated from the coordinates, forming a new index that is much more representative of the state of the stratosphere. The results show a very clear pattern of zonal wind and temperature regimes in the stratosphere. Furthermore, from each of these phases, there are physical connections to characteristics in the troposphere on a monthly to seasonal basis. These include the distribution of tropical cyclone activity, the El Niño / Southern Oscillation (ENSO), and the extratropical pattern. This new framework for monitoring the QBO is shown to be much more applicable to seasonal forecasting. Compare the EOF-constructed oscillation to a 52-month reanalysis segment

OKpowdah

OKpowdah

 

Rapid Clearing Expected This Evening

I have been really slacking as of late on the blogging ... hoping to fix that! Mediocre line of storms developed over the central Shenandoah Valley this afternoon and prompted a local blue box from Sterling around Charlottesville. There was a single report of wind damage in the city limits as well ... so congrats Sterling on the verification. Another line of storms lies further west from west-central Illinois through IND and down into LEX/central Kentucky ... high level blow off from this activity will likely stay clear of the area in at least the near term and allow for good rapid west to east clearing this evening. The clear skies early, excess moisture, and generally light winds will set the stage for some patchy overnight and early morning fog in areas that saw rain this afternoon (mainly the KSHD/KCHO area). This is not really anything new as this general area has seen patchy fog the last several mornings.

thunderman

thunderman

 

Severe WX Outlook Friday, June 28th: Northeast/mid-Atl.

An upper level trough across the Great Lakes is associated with areas of surface low pressure in and around New York State. Bands of showers and thunderstorms have been pinwheeling through the eastern United States as a result. By afternoon, more organized thunderstorm development is expected and some storms could become severe. Isolated severe thunderstorm threat... Low pressure is spinning across New York State. An area of increased wind shear is in place along the east of the Appalachians. Satellite imagery has indicated that much of the region has broken out to at least partial sunshine. This is creating moderately steep lapse rates and with cooler temperatures aloft associated with a 500mb trough, that steepness continues into the mid-levels. A rich southerly flow continues to keep dew-points on the higher side with most stations in the upper 60's to lower 60's. As far as forcing goes, there there is a weak frontal boundary movingly slowly eastward across the Appalachians. The higher resolution models couple that disturbance with an unstable air-mass and develop isolated thunderstorms and broken line segments across the Northeast by mid-afternoon. Some of the obstacles include a marine influence and some shower activity across southern New England, which may limit just how much the atmosphere can destabilize. However, elevated amounts of wind shear can promote updraft formation and some strong to severe thunderstorms. The coverage of these storms is not anticipated to be widespread in New York and New England. With cooler 500mb temperatures, there is a marginal hail threat with some of the stronger updrafts. Damaging winds seems to be the biggest concern with a relatively low, but still mention-able tornado threat, especially given the relatively low ML LCL's. Climo would not favor widespread severe activity given a south wind, but a coastal front could have some interaction with the upper level setup, which may slightly enhance convective activity. Convection is trying to initiate as of midday, but the focus is from early to mid afternoon across the Appalachians and late afternoon in southern New England for any strong to potentially severe storms. Numerous severe thunderstorm threat... Further south, stronger wind shear combines with more impressive daytime heating to warrant a threat of numerous strong to severe thunderstorms. The focus for this extends from southeastern Pennsylvania and western New Jersey and points southwest. Here there is a threat of large hail, damaging winds and also isolated tornadoes, especially given bulk shear values near or possibly above 50kts this afternoon.

Quincy

Quincy

 

Severe WX Outlook Through Friday Morning: NE/mid-Atl.

Low pressure develops across Pennsylvania later today and I am expecting at least some isolated severe thunderstorms across the region. Isolated thunderstorm threat... Satellite imagery shows mostly clear skies with just some high clouds across eastern Pennsylvania and New Jersey. Daytime heating is expected to push surface temperatures well into the 80's along with dew-points that are already in the upper 60's to lower 70's. In the warm sector well ahead of a cold front (east of the Appalachians in the mid-Atlantic states), a few thunderstorm cells or clusters could develop and become marginally severe this afternoon. As the cold front approaches, a squall line is depicted on the higher resolution models. This may cause isolated wind damage, especially across eastern Pennsylvania and western New Jersey. NAM forecast MLCAPE values are modest at best, near 1000 J/kg in spots. Some hail is possible in the stronger storms, but large hail is not a major threat. Due to the relatively late timing, the severe threat is a bit more unclear across portions of New York State. Even with a loss of daytime heating, proximity to deepening low pressure may cause strong to isolated severe thunderstorms to continue into the overnight period and through the pre-dawn hours of Friday. Although the threat is relatively low due to a lack of directional wind shear, the northern portion of this isolated threat zone will see increased shear after sunset as low pressure amplifies. The late timing does not climatologically favor nighttime tornadic development, but a quick spin-up could be possible, mainly in northeastern Pennsylvania, northwestern New Jersey and portions of southern New York State. In Connecticut... Although skies are breaking for sunshine across southwest portions of the state, there is a lack of a trigger mechanism to fire off any storms. MLCAPE values may increase to near 500 J/kg in parts of the state. SBCAPE looks more impressive, but with poor mid-level lapse rates, severe thunderstorm activity is not anticipated. Some pop-up thunderstorms are possible late in the afternoon and some embedded thunderstorms are expected overnight, especially west of the Connecticut River.

Quincy

Quincy

 

Flash Flood and Possible Isolated Tornado Threat Thursday - Saturday

An area of low pressure is expected to come out of the Gulf of Mexico and up the east coast, while another disturbance approaches us from the West in the Thursday - Saturday time frame. These two systems will attempt to pump in a rich plume of moisture from the south and east, setting the stage for heavy downpours with any showers and thunderstorms that develop. No widespread severe weather is expected, but I would not rule out an isolated tornado with this system(s) ... with a somewhat favorable wind field, despite the lack of instability. Remember, you don't need a crap load of instability for rotating updrafts/supercells Still a lot of certainty, but the potential for the above is certainly there. 12z GFS from this morning valid 00z Friday.

thunderman

thunderman

 

May 31, 2013 Oklahoma City Traffic/Chaser Debacle

I generally stay away from opinion posts in this blog, but the events that transpired yesterday deserve attention. First, I think that it needs to be pointed out that chasers and spotters provide invaluable information to the National Weather Service in the form of ground truth. This is a concept that most of the general public (and even some meteorologists) on the East Coast do not fully understand. Without these folks burning their personal gas, warning lead times could be substantially different in some cases. With that said, there are quite a few amateurs out there that know just enough to find a storm and get themselves (and potentially others) killed. These people do not have a handle on basic storm structure and thus do not know how to attack a storm a properly. There are also the experienced guys that know better, but still conduct storm intercepts in an unsafe manner to get their video on CNN. Both of these groups are ruining what used to be a prestigious hobby. Now the million dollar question is what do we do about this problem on the chaser side of the things? It is a tricky question, but I believe that it is going to come down to law enforcement cracking down on obvious storm chasers breaking minor laws (slightly speeding, etc). Is it right? No, but I really do think that this is what is going to end up happening. Then you have the other side of spectrum that contributed to the traffic mess … broadcast meteorologists. Some of these broadcast meteorologists are completely incompetent and they simply have no business on television … much less in a high risk area such as Oklahoma. We are asking for a disaster when we have people, such as Mike Morgan at KFOR, that are telling people to attempt to drive away from a tornado after warnings are out. Keep in mind that this goes against pretty much every tornado/severe weather safety checklist. If you are going to leave, do so well before the storms fire (we are talking 10am). How these people are allowed to stay on the air with a NWA seal is beyond me. Put bluntly, they are an embarrassment to the profession. Broadcast meteorologists need to be held accountable for spewing such garbage, before a large number of people get killed because of inaccurate safety information. If an air traffic controller goes against protocol and puts the public’s safety in jeopardy then they are reprimanded. This should be no different for broadcast meteorologists during severe weather. I would love to see the operational meteorological community as a whole step up and do what needs to be done … hold these incompetent meteorologists accountable.

thunderman

thunderman

 

Recap: Tornadoes in New York, May 29th, 2013

Two tornadoes (an EF-2 and an EF-1) touched down in eastern New York on Wednesday, both around 7:00 p.m., according to the National Weather Service (NWS). The stronger tornado, an EF-2, had winds of up to 125 MPH and caused damage along a relatively wide and long path. The tornado width was estimated at 1 mile wide with a track length of 17 miles from Florida to Rotterdam. The second tornado formed just to the southwest of the EF-2 tornado, around the same time. It was a weaker and shorter-lived tornado, but was associated with the same powerful squall line that was moving east-southeast across New York. An upper level shortwave disturbance passed across New York state on Wednesday. Daytime heating across the state helped destabilize the atmosphere. Veering winds aloft created an environment that was conducive for the formation of tornadoes. I was actually chasing the EF-2 tornado, but was too far west to catch up to it. Heavy rain, flash flooding and traffic didn't help matters. As I drove into the Rotterdam area along I-90, I noticed cars parked under overpasses. While they may have not witnessed the tornado, I'm sure they experienced strong winds and may have been aware of the Tornado Warning. Personally, I did not see a lot of damage, but the tracks of the tornadoes were mainly south of I-90, which was my route of travel. PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE ALBANY NY 1209 PM EDT FRI MAY 31 2013 ...PUBLIC INFORMATION STATEMENT... TORNADO TOUCHDOWN IN MONTGOMERY AND SCHENECTADY COUNTIES ON WEDNESDAY MAY 29 2013. LOCATION... BEGAN IN FLORIDA IN MONTGOMERY COUNTY NEW YORK TO ROTTERDAM IN SCHENECTADY COUNTY NEW YORK. DATE...05/29/2013. ESTIMATED TIME...647-700 PM. MAXIMUM EF SCALE RATING...EF-2. ESTIMATED MAXIMUM WIND SPEED...125 MPH. ESTIMATED PATH WIDTH...1 MILE WIDE. PATH LENGTH...17 MILES. BEGINNING LAT/LON...42.8457/-74.2034 ENDING LAT/LON...42.8042/-74.0208 * FATALITIES...NONE. * INJURIES...1. * THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO CHANGE PENDING FINAL REVIEW OF THE EVENT AND PUBLICATION IN NWS STORM DATA. SUMMARY...PATH WIDTH WAS CONSISTENT ALONG THE ENTIRE PATH LENGTH. MAXIMUM DAMAGE INCLUDED ROOFS TORN OFF OF MULTIPLE STRUCTURES AND HIGH TENSION POWER LINE TOWERS TOPPLED. LARGE NUMBER OF HARD AND SOFT WOOD TREES WERE EITHER TOPPLED...UPROOTED AND OR SHEARED. WIDESPREAD POWER OUTAGES OCCURRED AS WELL. ****************************************************** PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE ALBANY NY 1241 PM EDT FRI MAY 31 2013 ...PUBLIC INFORMATION STATEMENT... TORNADO TOUCHDOWN IN SCHOHARIE COUNTY ON WEDNESDAY MAY 29 2013. LOCATION... SUMMIT AND EAST JEFFERSON IN SCHOHARIE COUNTY NEW YORK. DATE...05/29/2013. ESTIMATED TIME...657 PM TO 702 PM. MAXIMUM EF SCALE RATING...EF-1. ESTIMATED MAXIMUM WIND SPEED...100 MPH. ESTIMATED PATH WIDTH...200 YARDS. PATH LENGTH...2 MILES. BEGINNING LAT/LON...42.515196/-74.554181 ENDING LAT/LON...42.522471/-74.578385 * FATALITIES...NONE. * INJURIES...NONE. * THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO CHANGE PENDING FINAL REVIEW OF THE EVENT AND PUBLICATION IN NWS STORM DATA. SUMMARY...BRIEF TOUCHDOWN ALONG RIDGE LINE SEEN FROM JUNCTURE OF DUTCH HILL ROAD AND WHARTON HOLLOW ROAD. DOZENS OF SOFT AND HARD WOOD TREES FALLEN IN DIFFERENT DIRECTIONS AND SHEARED OFF. ALSO TREES DOWN IN DIFFERENT DIRECTIONS ALONG ENID ROAD AND PERAGLIA ROAD. Here's a look at radar imagery at 7:00 p.m. when both tornadoes were on the ground: Notice overlap of strong bulk wind shear and MUCAPE leading up to the touchdowns: Here's a look at storm reports from across the area: Here are the tornado tracks to date (2013) in the region: Here's a look at my closest pass to the EF-2 tornado, which was basically at the time that it was reported to have lifted off the ground:

Quincy

Quincy

 

Severe WX Outlook, Northeast: Wednesday, May 29th

As a warm front lifts into the Northeastern United States on Wednesday, a warmer, more humid air-mass floods into the Northeast. Some thunderstorm development is forecast and some of those storms may be capable of reaching severe limits, particularly across portions of New York and west-central New England. Low threat (Conditions are somewhat favorable for severe thunderstorms) Interior New England, New York, northwestern New Jersey and norther Pennsylvania: As a warm front clears, an increasingly unstable air-mass overapreads the area, along with increasing dew-points. Once lingering showers, patchy fog and drizzle clear, some daytime heating will begin to fuel the atmosphere. The severe thunderstorm threat relies on a few factors. Although daytime heating is important, it should be noted that bulk wind shear values are forecast to be low to moderate, with the strongest helicity displaced northeast into central and northern New England. A line or broken lines of thunderstorms are expected to develop along a trough during the afternoon. The focus is on central and eastern New York, as well as western Massachusetts and southern Vermont. This area has a fair amount of overlap with respect to wind shear, instability, helicity and proximity to a shortwave passing near the Canadian-United States border. MLCAPE and lifted index values are somewhat supportive of severe thunderstorms, especially assuming there is a fair amount of sunshine to promote destabilization. It is also in this region that both the ARW and NMM model forecast reflectivities indicate a relatively strong squall line dropping southeast between about 5 p.m. and 9 p.m. local time. The threat appears to be mainly strong winds, but isolated hail is another possibility. Although the tornado threat is low, should wind shear coincide enough with higher helicity values, there could be a spin up or two. This area is being monitored and may be upgraded to a moderate threat of severe thunderstorms, should model guidance trends continue. Marginal threat (Conditions are marginally favorable for severe thunderstorms) Elsewhere in green: A few scattered showers and thunderstorms are possible across the region, as far south as the middle Appalachians. Across the coastal plain of New England, decaying thunderstorms could hold together as they approach Interstate 95. Threat definitions...(Severe thunderstorm = wind gusts to 58 MPH and/or >1" hail) Marginal: Conditions are marginally favorable for severe thunderstorms. Low: Conditions are somewhat favorable for severe thunderstorms. Moderate: Conditions are moderately favorable for severe thunderstorms. High: Conditions are very favorable for severe thunderstorms. Extreme: Conditions are extremely favorable and dangerous thunderstorms are likely. *Disclaimer* The intent here is somewhat different than SPC severe weather outlooks. The green, yellow, etc. shadings do not directly correlate between SPC and my own outlooks. I'm still getting a feel for these outlooks, but I imagine that in more impressive severe setups, I will use red and orange colors a bit more generously than SPC might. Also, green colors on my maps indicate a marginal severe weather threat, while on SPC it corresponds to a general thunderstorm (not necessarily severe) threat.

Quincy

Quincy

 

Severe WX Outlook, Mid-Atl.: Wednesday, May 15th

As a warm front lifts into the Northeastern United States on Wednesday, some thunderstorm development is forecast and some of those storms may be capable of reaching severe limits. Low threat (Conditions are somewhat favorable for severe thunderstorms) Central Pennsylvania and portions of Maryland: A warm front is expected to lift into the Northeast on Wednesday. The focus is across the warm sector where some strong wind shear combines with surface/low-level instability to enhance the severe thunderstorm threat. The strongest wind shear and helicity values are projected to move across New York and New England, but there may be enough overlap across portions of the mid-Atlantic states to initiate some severe thunderstorms. The threats at this time look to be for damaging winds and isolated tornadoes. This is heavily dependent on timing and the ability of enough daytime heating to steepen lapse rates. The 15z SREF was showing an area of 1000-2000 J/kg MLCAPE across southern Pennsylvania during Wednesday afternoon. Marginal threat (Conditions are marginally favorable for severe thunderstorms) Elsewhere in green: Although a large area is outlined in green, no organized area of severe thunderstorms is expected here. However, there is marginal atmospheric support for a few damaging wind gusts. Threat definitions...(Severe thunderstorm = wind gusts to 58 MPH and/or >1" hail) Marginal: Conditions are marginally favorable for severe thunderstorms. Low: Conditions are somewhat favorable for severe thunderstorms. Moderate: Conditions are moderately favorable for severe thunderstorms. High: Conditions are very favorable for severe thunderstorms. Extreme: Conditions are extremely favorable and dangerous thunderstorms are likely. *Disclaimer* The intent here is somewhat different than SPC severe weather outlooks. The green, yellow, etc. shadings do not directly correlate between SPC and my own outlooks. I'm still getting a feel for these outlooks, but I imagine that in more impressive severe setups, I will use red and orange colors a bit more generously than SPC might. Also, green colors on my maps indicate a marginal severe weather threat, while on SPC it corresponds to a general thunderstorm (not necessarily severe) threat.

Quincy

Quincy

 

Recap: Tornado in Massachusetts, May 9th, 2013

The National Weather Service (NWS) reported that an EF-0 tornado touched down in eastern Massachusetts Thursday afternoon, shortly after 4:30 p.m. An upper level low lifted northward through New England on Thursday. An unseasonably cold air mass was in place, resulting in cold temperatures aloft. It was the combination of low Lifted Condensation Levels (LCL's) and moderate wind shear aloft that helped create an environment that was marginally supportive of tornado development. It is possible that a land-sea interaction with winds off of the nearby ocean may have played a role in spawning this tornado. The NWS reported that it was a case of a cold air funnel. The tornado touched down in Stoughton, M.A. in Norfolk County and stayed on the ground for 0.25 miles. The tornado was a strong EF-0 with maximum sustained winds of 85 MPH. Damage was minimal, but a local car dealership reported seeing the tornado and had some vehicles blown around by the winds. Looking back at historical tornadoes in the Northeastern United States, the helicity values and amounts of instability in place on Thursday were relatively low compared to prior tornadic events. However, it was the low LCL heights and moderate wind shear that did elevate the tornado potential somewhat. On a scale of 0-5, 0 being unfavorable and 5 being highly favorable for tornadoes (based on local climatology), the environment yielded a value of 1.9. A note that a 2.5 value would be equal to the mean of past tornadoes. PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE TAUNTON MA 158 PM EDT FRI MAY 10 2013 ..TORNADO CONFIRMED IN STOUGHTON IN NORFOLK COUNTY MA LOCATION... STOUGHTON IN NORFOLK COUNTY MA DATE...MAY 9 2013 ESTIMATED TIME...431 PM EDT MAXIMUM EF-SCALE RATING...EF0 ESTIMATED MAXIMUM WIND SPEED...85 MPH MAXIMUM PATH WIDTH...50 YARDS PATH LENGTH...0.25 MILES BEGINNING LAT/LON...42.10N / 71.10W ENDING LAT/LON...42.10N / 71.10W * FATALITIES...0 * INJURIES...0 * THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO CHANGE PENDING FINAL REVIEW OF THE EVENT(S) AND PUBLICATION IN NWS STORM DATA. ..SUMMARY THE NATIONAL WEATHER SERVICE IN TAUNTON MA HAS CONFIRMED A BRIEF TORNADO TOUCHDOWN IN STOUGHTON MA ON MAY 9 2013. THE TORNADO TOUCHED DOWN AT A CAR DEALERSHIP ON ROUTE 138 WHERE IT WAS CAPTURED BY A SECURITY CAMERA AND RECORDED ON CELL PHONE CAMERAS BY SEVERAL OF THE DEALERSHIP EMPLOYEES. THREE RV TRAILERS...WEIGHING ABOUT 5000 POUNDS EACH...WERE PUSHED BACK ABOUT 6 FEET AGAINST A CHAIN LINK FENCE. ONE TRAILER WAS LIFTED ABOUT 15 FEET INTO A LIGHT POLE BUT LANDED ON ITS WHEELS WITH MINIMAL DAMAGE. AN ALUMINUM DOOR ABOUT 20 FEET HIGH AND 15 FEET WIDE WAS BLOWN OUT OF THE SERVICE GARAGE. EYEWITNESSES REPORTED CEILING TILES BEING LIFTED INSIDE THE DEALERSHIP AS THE TORNADO PASSED OVERHEAD. THE TORNADO ENTERED A WOODED AREA JUST TO THE NORTHEAST OF THE DEALERSHIP. ABOUT 0.25 MILES AWAY...TWO LARGE PINE TREES WERE DOWNED ON ERICA DRIVE AND DEAN ROAD BEFORE IT DISSIPATED. BASED UPON A SURVEY OF THE DAMAGE...THE TORNADO IS CLASSIFIED AS EF0 ON THE ENHANCED FUJITA SCALE WITH MAXIMUM WINDS OF 85 MPH. THE PATH LENGTH WAS 0.25 MILES AND THE MAXIMUM WIDTH WAS ABOUT 50 YARDS. Here's a look at radar imagery about a half hour before the time of the tornado: The Supercell Composite Parameter was relatively low, although some slightly higher values did target the area near the tornado touchdown: The only severe weather report in the Northeast on Thursday was that tornado in Massachusetts!

Quincy

Quincy

 

Severe WX Outlook, NE, Mid-Atl.: Saturday, May 11th

As a cold front moves towards the East Coast on Saturday, some thunderstorm development is possible during the afternoon and early evening hours. Low threat (Conditions are somewhat favorable for severe thunderstorms) Mid-Atlantic region (east of Appalachians), lower Hudson Valley and SW New England. Conditions will destabilize in a warm, somewhat moist air-mass before an approaching cold front swings from west to east through the area. The biggest question mark is how much daytime heating will take place. Across Virginia, there will likely be more heating and with higher dew-points here as well, in the mid-60's, some thunderstorm development is likely. Some of these storms could reach severe limits. Further north, across eastern Pennsylvania, interior New Jersey, southeastern New York, northwestern Connecticut and the Berkshires, the threat of severe thunderstorm activity relies heavily upon daytime heating. The NAM continues to show some scattered showers and mid-level moisture limiting the destabilization process. With that said, the SREF/NAM/GFS still show a narrow finger of somewhat unstable air in this region. CAPE values between 250-500 J/kg, LI values around -2 and bulk shear around 30kt could result in a few thunderstorms reaching severe limits. Dew-points are progged to reach the lower 60's by the NAM. The 18z NAM simulated radar shows a squall line developing from Baltimore to Philadelphia to Poughkeepsie. However, this line is relatively short-lived as it collapses upon reaching the coastal plain and western Connecticut. It should be noted that helicity values increase towards the northeast, especially in New England. This may work to offset the slightly less unstable atmosphere. Bottom line, some thunderstorms may produce damaging winds from the mid-Atlantic region into southwestern New England. Some hail is possible here, but there's a stronger potential for severe hail further south. The tornado risk is relatively low, although Significant Tornado Parameter (STP) values indicate that a brief tornado or two could form anywhere in the yellow shading. Local topography across the Appalachians could aid in some rotation with any cells. When running the numbers, the tornado parameters are a bit below the mean tornado environments for historic tornadoes in the region, but are higher than what verified on Thursday with the brief EF-0 tornado in eastern Massachusetts. A few renegade thunderstorm cells could fire ahead of a cold front Saturday afternoon, especially across Virginia, where there may be a few supercells. A squall line along the cold front is more likely, advancing through eastern Pennsylvania early in the afternoon and towards the NYC metropolitan area and the coastal plain by mid to late afternoon. Instability will be key in the formation of and ability of this line to maintain itself. Marginal threat (Conditions are marginally favorable for severe thunderstorms) Mid and upper Appalachians and portions of southern New England. Shower and thunderstorm activity is likely across the entire area, but less daytime heating will limit the severe weather threat. As one moves eastward, especially towards the coastal plain of New England, the threat decreases significantly. Threat definitions...(Severe thunderstorm = wind gusts to 58 MPH and/or >1" hail) Marginal: Conditions are marginally favorable for severe thunderstorms. Low: Conditions are somewhat favorable for severe thunderstorms. Moderate: Conditions are moderately favorable for severe thunderstorms. High: Conditions are very favorable for severe thunderstorms. Extreme: Conditions are extremely favorable and dangerous thunderstorms are likely. *Disclaimer* The intent here is somewhat different than SPC severe weather outlooks. The green, yellow, etc. shadings do not directly correlate between SPC and my own outlooks. I'm still getting a feel for these outlooks, but I imagine that in more impressive severe setups, I will use red and orange colors a bit more generously than SPC might. Also, green colors on my maps indicate a marginal severe weather threat, while on SPC it corresponds to a general thunderstorm (not necessarily severe) threat.

Quincy

Quincy

 

April Forecast Verification for Inland Connecticut

I've been creating daily 6-day forecasts for the better part of this year, with a focus on inland Connecticut. Before making any forecast, I take a close look at the computer model forecasts through Day 6, including a few forecast techniques to see how verification pans out. In April, I had 29 days worth of data, out of a possible 30, to measure forecast accuracy. As expected, forecast error generally increases with time. It is interesting to note a spike at Day 5 and a decrease at Day 6. That goes back to two particular days that had poor Day 5 forecasts vs. actual temperatures. The spread is relatively uniform as well. The error with the NAM model does seem to increase faster with time than the others, which is not a surprise. DGEX data was used for Days 5 and 6. With respect to my own forecasts, I measure verification as a mean of inland temperatures across the state. When I look at the computer models, I choose Meriden (KMMK) as a central point. This is due to its location near the center of the state. With that said, since my own verification is slightly different than the control (KMMK), this may skew results slightly. For that reason, I will be creating 6-day forecasts specifically for Meriden as a go-forward. The Euro and MAV MOS rank fairly close, but it is very interesting to note that the negative (cold) bias the Euro has is almost a mirror reflection of the MAV MOS positive (warm) bias: The MAV MOS appears to correct some of its bias towards Days 5 and 6. That can perhaps be partially explained by the fact that MOS is skewed towards climatological temperatures. The NAM also seems to have somewhat of a cool bias. I re-project highs from the NAM for Day 1, but that re-projection seems to over compensate the bias, at least in the case of April. Explaining the models/forecasts... Q: My forecast high temperatures for inland Connecticut. (mean of inland stations) MAV MOS: Forecast high temperatures for KMMK. (06z model run) ECMWF: Forecast grid-point high temperatures for KMMK. (00z model run) NAMDGEX: Approximate high temperatures for KMMK. These values are interpolated off of a graphical forecast, so the numbers are estimated. I use the NAM for Days 1-4 and the DGEX for Days 5 and 6. (06z model runs) 850mb: An 850mb forecast technique that I have been working on for quite some time. Because this technique is based off of Danbury (KDXR), that station is used for verification. LAMP MOS: Forecast high temperatures for KMMK. (most recent run in morning) NAM Re-projection: This takes into account the actual 9 a.m. temperature vs. the 06z forecast for 9 a.m. for KMMK. That error is then re-projected into the high temperature forecast. Example: If the 9 a.m. temperature was 2°F warmer than forecast, then 2°F is added to the high temperature forecast. Consensus: A mean of each forecast above, including my previous forecast (continuity) How accurate was a Euro/MAV MOS blend? Well, not only do the opposing biases balance out close to zero, but the overall forecast error was less than any other forecast technique for Days 2-6: It's pretty interesting to see the results. It goes beyond comparing computer model verification. In order to become a better forecaster, I want to see what forecasts have worked out, which ones haven't and if I have any biases. This is only one month's worth of data, so more will need to be compiled over the long-run to see how models perform. I also expect that different models/techniques will perform differently depending on the season, weather pattern, etc.

Quincy

Quincy

 

Severe WX Outlook, NE, Mid-Atl.: Wednesday, April 24th

A cold front is forecast to move from west to east across the East Coast on Wednesday. The result could mean scattered thunderstorms along the front, along with a few severe thunderstorms. (Marginal threat) Middle Appalachians into DE, PA, inland NJ and interior NY. A similar setup to this past Friday is expected on Wednesday, with a cold front moving across the area during the afternoon and evening hours. The only difference here is that the cold front is not as strong as that scenario (last Friday) and less convective activity is expected. Ahead of the cold front, some marginal destabilization is expected as near-surface temperatures rise into the 70's, slightly steepening lapse rates. As a result, Lifted Index values between 0 and -2 are forecast. MUCAPE is meager, with values generally less than 500 J/Kg. Although dew-points are forecast to be in the mid to upper 50's, wind shear and helicity is forecast to be somewhat less than the last event. Bulk shear of 30 to 50kt is forecast across eastern Pennsylvania, coupled with storm relative helicity values of 100-200, so some isolated damaging wind gusts are possible. (Low threat) Interior Virginia, Central Maryland and portions of eastern Pennsylvania. In this region, the timing of the cold front corresponds closely with the peak daytime heating. There's also a sliver of 500 to 1000 J/Kg CAPE values expected in south-central Pennsylvania, down into Maryland and Virginia. It's also in this general area that there is a marginal tornado threat, however the tornadic setup on Wednesday is also less impressive than it was last Friday. Graphics to differentiate between the damaging wind and tornado threats: (No appreciable severe weather threat) Southern New England, Long Island and coastal plain of New Jersey. The cold front does not make it into this area until midnight or a few hours afterward. At that time, moisture is very limited, wind shear values relax and there should be little to no instability to fuel thunderstorm activity. Threat definitions...(Severe thunderstorm = wind gusts to 58 MPH and/or >1" hail) Marginal: Conditions are marginally favorable for severe thunderstorms. Low: Conditions are somewhat favorable for severe thunderstorms. Moderate: Conditions are moderately favorable for severe thunderstorms. High: Conditions are very favorable for severe thunderstorms. Extreme: Conditions are extremely favorable and dangerous thunderstorms are likely. As the spring season goes forward, I will be making more severe weather outlooks. Any feedback is appreciated and I am still working on the outlook/threat scale. I would like to compare forecasts to verification in the future, so some thought will be needed to address just how best to do so. *Disclaimer* The intent here is somewhat different than SPC severe weather outlooks. The green, yellow, etc. shadings do not directly correlate between SPC and my own outlooks. I'm still getting a feel for these outlooks, but I imagine that in more impressive severe setups, I will use red and orange colors a bit more generously than SPC might. Also, green colors on my maps indicate a marginal severe weather threat, while on SPC it corresponds to a general thunderstorm (not necessarily severe) threat.

Quincy

Quincy

 

Recap: Tornado in New York, April 19th, 2013

The National Weather Service (NWS) confirmed that an EF-1 tornado touched down in New York state Friday evening, shortly before 8 p.m. A strong cold front moved across Pennsylvania and New York state late Friday evening. At the same time, a marginally unstable air-mass was in place closer to the surface. With moderate to strong wind shear in place and significant storm relative helicity in place, the stage was set for damaging winds and even a marginal tornado threat. As a result, a Tornado Watch for a large portion of Pennsylvania and New York state. A tornado touched down near Bainbridge, N.Y. in Chenango County and stayed on the ground for 3.2 miles. The tornado was a strong EF-1 with maximum sustained winds of 110 MPH. Looking back at historical tornado environments in the same general area, the wind shear and helicity values in place on Friday were actually more "severe" than the climatological mean for past tornadoes. The only thing that was lacking was instability, as there was very little in place. Despite this fact, strong, twisting and turning winds aloft combined with an approaching squall line ahead of a cold front resulted in the tornado. PUBLIC INFORMATION STATEMENT...UPDATED NATIONAL WEATHER SERVICE BINGHAMTON, NY 954 AM EDT MON APR 22 2013 ...TORNADO CONFIRMED FROM 4 SSE BAINBRIDGE IN CHENANGO COUNTY TO 3 S SIDNEY IN DELAWARE COUNTY NEW YORK... UPDATED DATA ON LAT/LON POINTS AND WIDTH. LOCATION... FROM 4 SSE BAINBRIDGE IN CHENANGO COUNTY TO 3 S SIDNEY IN DELAWARE COUNTY NEW YORK DATE...APRIL 19 2013 ESTIMATED TIME...753 PM TO 758 PM EDT MAXIMUM EF-SCALE RATING...EF1 ESTIMATED MAXIMUM WIND SPEED...110 MPH MAXIMUM PATH WIDTH...200 YARDS YARDS PATH LENGTH...3.2 MILES BEGINNING LAT/LON...42.2481N / 75.4516W ENDING LAT/LON...42.2674N / 75.3939W * FATALITIES...0 * INJURIES...0 * THE INFORMATION IN THIS STATEMENT IS PRELIMINARY AND SUBJECT TO CHANGE PENDING FINAL REVIEW OF THE EVENT(S) AND PUBLICATION IN NWS STORM DATA. ..SUMMARY THE NATIONAL WEATHER SERVICE IN BINGHAMTON, NY HAS CONFIRMED THAT A TORNADO TOUCHED DOWN ABOUT 4 MILES SSE OF BAINBRIDGE IN CHENANGO COUNTY...TRACKED NORTHEAST ABOUT 3.2 MILES...AND THEN ENDED ABOUT 3 MILES SOUTH OF SIDNEY IN DELAWARE COUNTY NEW YORK FROM 753 PM EDT TO 758 PM EDT ON APRIL 19 2013. THE TORNADO TOUCHED DOWN BETWEEN INTERSTATE 88 AND HIGHWAY 206...ON EAST AFTON ROAD...WHERE 2 POWER POLES WERE SNAPPED AND A CAR WAS DESTROYED BY A LARGE TREE BRANCH. ANOTHER VEHICLE WAS ALSO DAMAGED. SEVERAL TREES WERE SNAPPED OR UPROOTED. A BARN HAD MINOR ROOF DAMAGE. THE TORNADO CONTINUED NORTHEAST AND CROSSED HIGHWAY 206...WHERE A FARM EQUIPMENT BUILDING AND A MOBILE HOME WERE HEAVILY DAMAGED...AND A STORAGE TRAILER WAS DESTROYED. OTHER NEARBY HOMES HAD MINOR DAMAGE...AND A CARPORT WAS LIFTED AND MOVED 75 FEETFARTHER DOWN ITS PATH...THE TORNADO INTENSIFIED TO A HIGH END EF1 STRENGTH WHILE TRAVELING IN THE VICINITY OF HOUCK DRIVE. IN THIS AREA IT UPROOTED OR SNAPPED MANY 1 TO 2 FOOT DIAMETER TREES ALONG ITS PATH...BOTH HARDWOODS /MAPLES/ AND SOFTWOODS /PINES/...WITH THE LARGEST MORE THAN 3 FEET WIDE. IT ALSO CAUSED STRUCTURAL DAMAGE TO A SINGLE FAMILY RESIDENCE AND GARAGE...WHILE TRANSPORTING A SIGNIFICANT AMOUNT OF DEBRIS A HUNDRED YARDS OR MORE. THE TORNADO THEN CROSSED INTO DELAWARE COUNTY...DOWNING SEVERAL MORE TREES ON SOME PROPERTIES ALONG HIGHWAY 8 BEFORE DISSIPATING. Here's an SPC archived radar image from 00z, just minutes after the tornado touched down. A noticeable kink can be seen along the squall line near the location of the tornado, along with the approximate track below it: Here are some more storm reports from Friday:

Quincy

Quincy

 

Updated: Severe WX Outlook, NE, Mid-Atl.: Friday, April 19th

A strong cold front approaches the Appalachians Friday afternoon and evening. Along that cold front, a squall line with thunderstorms is currently expected is develop. (Marginal threat) Middle Appalachians into Pennsylvania, northwestern New Jersey and interior New York: Daytime heating is expected to push temperatures into the low to mid-70's in the valley locations with mid to upper 60's in the higher elevations. Low and mid-level clouds will likely limit just how unstable the atmosphere can get. As a result, relatively low SBCAPE below 500 J/KG combined with near-zero or marginally negative Lifted Index values are expected. Despite strong winds aloft and effective bulk shear values increasing to 35 to 50kts along a cold front, the lack of instability will likely minimize the threat of severe weather. In addition, dew-points are forecast to stay in the 50's, perhaps coming close to 60° in Maryland and eastern Pennsylvania. However, a few isolated strong thunderstorms could develop Friday afternoon ahead of a cold front. There is a marginal threat of a few damaging wind gusts associated with a squall line along the cold front Friday afternoon into Friday night. (Low threat) Interior Virginia, east of the Appalachians: The atmosphere is likely to become slightly more unstable further south. SBCAPE values of 500 to 750 J/KG are forecast based off of SREF guidance. Lifted Index values as low as -3 combined with dew-points in the 60's and higher helicity values would support more strong to severe thunderstorm activity. Based off of this, there is a low threat of severe thunderstorms with damaging winds and large hail in this area. Some isolated thunderstorm cells are possible Friday afternoon, but locally severe storms could develop along a squall line Friday night as the cold front approaches. There is a marginal threat for an isolated tornado or two, but confidence in this potential is not particularly high at this point. (No appreciable severe weather threat) Connecticut (southern new England), NYC, Long Island and coastal plain of NJ/DE: With more of a marine influence allowing for less daytime heating, there is no appreciable threat of severe weather in these areas. Also, with the cold front not expected to move through until after midnight Friday (into early Saturday), this further implies that the severe weather threat is virtually non-existent. With that said, some locally strong wind gusts are possible as a decaying squall line and associated cold front moves through late Friday night into early Saturday morning. As the spring season goes forward, I will be making more severe weather outlooks. Any feedback is appreciated and I am still working on the outlook/threat scale. I would like to compare forecasts to verification in the future, so some thought will be needed to address just how best to do so. Learning is an ongoing process as I learned a lot about severe weather forecasting last spring/summer and there's still a lot more to cover. Experience also helps!

Quincy

Quincy

 

Severe WX Outlook, NE, Mid-Atl.: Friday, April 19th

A strong low pressure system is forecast to move up into the Great Lakes by Thursday and eventually into southeastern Canada late Friday into Saturday. A potent cold front associated with this storm will move towards the Appalachians by the second half of Friday. (For Wednesday and Thursday, severe thunderstorm activity is probable for the Mississippi Valley and portions of the western Ohio River Valley. I see a marginal setup for severe storms from Central N.Y. into the middle Appalachians. Even though a strong shortwave and upper level jet is expected to move into New York state and Pennsylvania, there are several factors which will likely limit the severe threat... With low-level moisture and clouds, daytime heating will not be maximized along the East Coast. Right now, the areas shown in green can expect gradually steepening lapse rates. However, dew-points are only expected to be in the mid-50's to around 60 north of Washington D.C., along with 2-meter temperatures in the mid-60's to lower 70's. eastern Pennsylvania and New Jersey could get well into the 70's, but with the front lagging further to the west, there really isn't much of a trigger to kick off any storms in that area. The SREF/NAM/GFS/Euro are actually fairly similar in timing and overall evolution of this storm system. Without much heating, relatively low CAPE values are forecast. The SPC SREF does show a ribbon of slightly negative (0 to -2) Lifted Index values from central Pennsylvania southward. This indicates a marginally unstable atmosphere. As one goes further south into Virginia, the severe weather indices increase, including dew-points into the 60's. This is why that area is outlined in a "low" threat potential. Wind shear values are a bit more supportive for severe weather, but even here, the storm system loses some of its punch as it reaches the Appalachian mountains. Effective bulk shear of 40-45kts is forecast across the region. Some strong winds aloft are expected with the front, but this area of stronger winds lags far enough back to really minimize the severe weather threat. Overall threats... -Damaging wind gusts could be supported anywhere in the green or yellow shadings. -In the yellow shading, there's a very slight risk of hail and isolated tornadoes. -In New England, gusty winds are possible with a band of rain and thunderstorms late Friday night into early Saturday, but damaging winds are not terribly likely. As the spring season goes forward, I will be making more severe weather outlooks. Any feedback is appreciated and I am still working on the outlook/threat scale. I would like to compare forecasts to verification in the future, so some thought will be needed to address just how best to do so. Learning is an ongoing process as I learned a lot about severe weather forecasting last spring/summer and there's still a lot more to cover. Experience also helps!

Quincy

Quincy

 

Virtual Storm Chase

There is a great competition called Virtual Storm Chase that has been given new life (for bragging rights only). This is the same competition that was started over on the old wxchat forums several years ago (mid 2000s). For those that do not know what it is, I have a attached a PDF copy of the rules below. It is a great learning experience for those interested in severe weather forecasting and a great way for even meteorologists to keep sharp. http://virtualstormchase.info The site "appears" to be broke ... but once you register (free) and login it works. Rules: Rules _ VirtualStormChase.pdf

thunderman

thunderman

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